Furnace



' 25 efficiencies and with a minimum of attention. water tubes 33A extends upwardly from the header 25 455 by a bank oi' upwardly and forwardly sloping fuel feeder 4I is mounted in front-of this open- 55 Patented 'Maa 8,` 1938 i UNITED STATESl PATENT OFFICE Stoker Corporation, Worcester, Mass., a. corporation of Massachusetts Application May 19, 193s, serial No. 80,570

s claims. (ci. lio-4o) This invention relates to furnaces, and more water tubes I5, and the-drums'l2 and IIi'are con-- particularly to furnaces arranged'for the comnected by a bank of upwardly and, rearwardly bustion of fuel and the generation of steam. sloping water tubes I6. A transverse steam drum In one well-known type o'f furnace, the fuel isV I8 is mounted above the front water drum' I2, this 5 delivered to a. stationary grate by means of a steam drum being connected tothe steam-and- 5 stoking mechanism located at thel front of the water drum IIi by a row of steam tubes I9 which l furnacey and arranged to throw the fuel rearsupport refractory material 20 forming', a roof 'wardly. The grate is frequently of the dumping over the boiler. In association with the -boiler type having a plurality of sections which can be y there is provided afront wall 22 a rear wal1 23,

l operated independently. In such furnaces conand-acombustion chamber 24 located beneath 10 siderable manual labor is required in cleaning thetube bank I5. A baffle 26 extends upwardly the fires, and the operation cannot be performed 'and forwardly from the rear water drum II, and without the admission of large quantities of cold a baille 2l extends downwardly from the steamair and a resultant decrease in efliciency. 'The and-water drum' I0, these baiiles serving to guide l stoking mechanism is necessarily somewhat comanddirect the hot gaseous products of combusl15 plicated and expensive', since it must distribute tiongas theyv ow from the chamber 24 into conthe fuel over the entire area of the grate surface tact with the several tube bahks and thence to a with reasonable uniformity. Moreover, substangas outlet 28 in the rear of the steam-and-.water tial quantities of fly ash containing` combustible drum IU. i

matter are deposited in the gas passages of the The combustion chamber 24 is closed at the rear 20 boiler, and the removal and disposal of this maby a bridge wall comprising refractory material terial presents a further problem. 1 30 supported by a row of upright water tubes 3l It is accordingly one object of the invention to which extend downwardly from the rear water provide a furnace which can be operated at high drum `II to a transverse header 32. A- row of It is a further object of the invention to pro- 32 along the front surface ofthe refractory 30 4vide a comparatively simple, inexpensive and reand thence slopes upwardly and forwardly to liableapparatus for burning fuel partly in susv the front waterA drum I2. -The sloping portions pension and partly in a fuel bed. of the tubes 33 are located a substantial distance It is a further object of the invention` to probelow the tube 'bank I5, thus serving as a slag V30 vide an improved apparatusfor removing fly ash screen for the boiler. Y from a boiler and 'burning the'combustible mat- At the bottom vof the combustion chamber 24 ter therein. there is provideda suitable grate to support 4a -It is a further object of the invention to profuel bed and mov'e-it slowly toward the front 35 vide a simple and eicient method of burning wall 22. For this purpose I preferably utilize 2.135

fuel, particularly fuel in a crushed but not pui,- grate 35 of the .chain or traveling grate type.` verized form. y Therear portion of this grate i's located in the With these and other objects in view, as will be rear of the header 32, a slight space preferably apparent to those skilled in the art, the invenbeing provided between this header and the upper a0 tion resides in the combination of parts and the run of the grate. The front portion of the grate 40 steps of the process set forth in the specification extends beneath the front wall 22 and above an 1 and covered by the claims appended hereto. ash hopper 36 which is preferably of the closed Referring to the drawing illustrating one emtype. The grate 35 may be operated under either bodinient of the invention, and in which Ilike natural o-r forced draft, and suitable transverse reference numerals indicate like parts, y partitions 31 are provided between theupper and 45 The single figure .is a longitudinal section lower runs to provide several zones for the conthrough a steam generating furnace.` trol of the combustion air, as is customary. Air

'I'he embodiment illustrated comprises a steam is admitted to the respective Zones through openboiler of awell-known type having an upper rear ings 38 at the sides of the grate. transverse steam-and-waterdrum I0, a. Ylower, n 'I'he fuel bed is ymaintained by projecting-fuel 50 rear transverse water drum I I therebeneath, and to the'rear portion thereofy from the front of the l a front transverse water drum l2. v The drums furnace. For this purpose the front vwall v 22 Ill and II are connected by a bank of upright is provided with an opening 40 located a. subwater tubes I4, the drums II and I2,are connected stantial distance'above the grate, and a suitable axis at a substantially constant speed by any suitable source of power. Immediately. above the s feeder u-ond mmm the oa'smg 42 merels mount:-

ed a rotatable -feed regulating devicel Mv shaped to provide pockets Il in its periphery. This device- 4I is arranged to 'be rotated-about a horit zontal axis at a comparatively slow speed'by any suitable means, whichnpreferably provides for anA adjustment of the rate of rotation. 'I'he casing 42 is extended upwardly abovethe feed regulator Il to .provide afuel hopper 46. l An. appreciable quantity of solid material Vin the form of fine particles will be carried by the stantial proportion of combustible matter. In order to collect this dy ash and recover the heat values contained therein, a hopper I8 is provided in the rear of the` bridge wall III. 'I'his hopper communicates at the top with the space between the realwaterdrum Il and-the'rear wall 23,

so that solid particles which are carried rearf* wardlyover the top of the baille 26 and'enter' the downward pass at the rear thereof will fall by gravityY into the hopper. This deposit of material isfaided bycentrifugal force. since the gases make a sharp upward turnaround the banle one or 'more manually actuated gates- I9.'

In the operation of the invention the4 hopper is illled withA a suitable fuel, such las crushed but unpulverized coal. 'Ihe rotation of the'pocketed feed regulator M supplies fuel at a controlled rate to the rapidly rotating feeder Il which projThevilnetparticles of `fuel burnin suspension, while `the coarse particles fall on thefuel bed immediately in front of the header ll. The Aupper run of the grate ,35 travels slowly toward the front of the furnace, carrying the fuel/bed with it, the rear portion of the fuel being continuously replenishedby the fr esh fuelvwhich is-delivered by the feeder. Air for combustion enters throughthe lopenings It and flows upnothing but ash remains, this falling into the ash hopper It. -B uiiicient excessl air may belincombustion chamber 2l, the combustible matter v heating value thereof recovered. l

The bridge wall Il'is'well supported and cooled by the water tubes, it being understood that water flows ln'the tubes ll at theI rear ,Y contained in the ily ash being consumed and the ofthewalland upwardly innthe`tubes Matthes.

,o front ofthe wall. kThe upper portions of the tubes Il'cool the molten asliparticles carried by the gasesleaving the furnace and. prevent =theseparticles from adhering to the boiler tubes Il "Ihehielfdlntinechanlsm 'Ii celibe-.01.

i.cosiiparatively and inexpensivel construcdraft into the boiler gas passages. This material Aisknown as ily ash, and it may contain a sub- 21 kdirectly above the hopper. v'Ihe'hopper Il is shaped and arranged to deliver `,the collected material directlvto the portion ofthe 'grate Il in therear of the header l2. The discharge of this material from the hopper may bel-controlled .by f

jects the fuel rearwardly throughthe opening III. f

wardly through the grate so that combustion of. the fuel occurs, avnd at the front' ofi-the grate tion.sinceitproiectsallofthefuelto 'ofthe combustionelnmberandianot to distribute fuel uniformly over'a large areaasinprioreonstructlona. No

gag

sionbeforetheyreachthefuelbemandmoving" thefuelbedio thefrontofthefurnace.-

2..Afurnac compr-Ising walls forming a canbustion chamber. the front wail having an opening therein, an endless grate at the bottom of the combustion andhaving an upperrun arrangedto travel to the front ofthe furnace. anda feeding device arranged to mutuel rearwardly grate through the opening tothe rear portfon of the grate. l f3.1A furnace compsingwallsformingna can ybustion chamber, the front wall having an opmingltherein, an endless grate at the bottmn of the combustion chgambcr and having an upper rim arranged totravel to the front of thefurnace, a rotary feedingfdevice mounted adjacent laid opening 'and arranged to project fuel rearwardly therethrough over the .partimofA thesratedndmo/mppxy fuel to n roodmg devloe at a oonuouod me '4. Avsteam generating furnace comprilim a boiler, walls forming a combustion chamber beheath the boiler, a' grate at the hottom'of the combustion chamber-'and extending rearwardly beneath the rear wall .ot'the'conihustionzchamf ber and slightly spacedtherefrpm, a feedingl device arrangedtopmjectfuelrearwardlyfromthe iront of the furnace to the grate immediately in front of the rear wall, and means to eolbctily ash from'the boiler' and deposit it`on the grate in the rear of thevsaidflear wail, the-grate being movable to move the ily ash and ward the front of the furnace.

fueislo'wiyto 5. A steam generating furnace comprking a.

boiler. walls forming-a combustion" chamber beneath the boiler, a grate' at the bottom of the -Vcombustion chamber and extending V rearwardly beneath the rear wail of the n chamber and slightly spaced therefrom, a feeding device arranged to project fuel rearwardly from the front of the furnace'to the grate in frontoftherearwaihmeanstodireetthegaam v from the combustion chamber into contact withl theboilerinanupwardpassandthenrearwardly tooouoocny ashatthebottomotthedawnwardpasaanddeposit it on the'grateintherearofthesaidrear -wammograhemgmonbutommmedyam and fuel slowly toward the'front of the furnace. 6. generating furnace compl-illu a boiler,wallsforminga diamherbeneaththeboiienanendielgrateatthebottmnu f. 1

of the combustion chamber and having an upper run which extends rearwardly beneath the rear wall of the combustionehamberand slightly spaced' therefrom, the upper run being arranged to travel toward the front of the furnace, a feeding device arranged to project duel rearwardly frorn the front of the furnace tothe grate 'immediately in from; of the rear wall, and means GEORGE Mom. 

